Auto Clinic Reader Q & A Column: January 2004

Hooking Up
I was trying to replace the manifold air sensor on my car. Everything seemed to go so simply until I tried to plug the connector into the new harness on the sensor. One of the wires pushed right out the end of the connector. I pushed it back in partway, but now it works only intermittently. My Check Engine light comes on every few weeks, and I have to go under the hood and try to reseat the connector in the plug. My brother-in-law wants to just bypass the connector with a spade-lug connector like he used on his trailer hitch that he jury-rigged recently--but I don't think the engine management computer will be okay with that idea. Don't those sensor wires need to be shielded or something?
TOM PARKER
MEMPHIS, TN

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First off, never use those spade-lug connectors anywhere on a vehicle where they can get wet--they'll soon corrode and fail. Don't ask how I know this.

If you look closely at the part of the metal plug in your connector that pushes back when you plug it in, you'll see a couple of metal tabs that spring out of the body to keep it inside. There's a special tool, consisting of a small tube, that goes over the pin to retract the tabs and allow you to pull the pin free of the connector. Usually, you can remove the pin with a small screwdriver or sharp instrument by carefully pushing the tabs back manually. I save this technique for roadside emergencies.

Your tabs are probably bent in too far. Take a small screwdriver and bend them out a little, then reinsert the pin until you feel them click out. If the tabs are damaged or broken off (often seen when ham-fisted mechanics yank connectors apart hurriedly), you can get a new pin at an auto parts store and solder it onto the wire.

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CAR CARE TIP

Sticky and Greasy

It was late, and the engine assembly had gone well--until my partner tried to install the distributor into the top of the block and dropped the thrust washer into the hole. Two grown men were forced to do the boogaloo with an upside down Volkswagen engine while trying to get the washer to bounce back out. Then, it rolled across the shop floor and into a crack in the floor. I did my best to maintain my composure while he fished it out with a magnet. I decided that he needed some sleep. Okay, we both needed sleep. The next morning, it seemed like a good idea to install the distributor myself. Refreshed, I used my customary technique of gluing the washer to the distributor shaft with grease. This prelubed the washer, but it also kept it in place on the distributor shaft while I inserted it. This technique works for keeping all sorts of things in place while you install them. I use it for ball bearings, gaskets, washers, O-rings or anything that takes three or more hands to work with and is light enough to stick to the grease.

Put Your Donkey In Neutral
I was with a friend of mine the other day and noticed that when he stopped at traffic lights, he would move the shifter into Neutral. He said that when in New York some years ago, he learned this from a cabdriver who said it would double the life of the transmission. Any truth to this?
DOUGLAS SCHEIDT
VIA INTERNET

Sounds like a good way to wear out the linkage. Think about it--in Drive with the brakes applied, the transmission is totally stationary. Only the torque converter and the pump are spinning. But in Neutral, many of the gearsets in the trans are spinning. Add in the cycling of the valve body twice (once to shift into Neutral and once to shift back into Drive), and you have more parts to wear. Do the math.

Tired
The manual for my Nissan Xterra states the tire pressure should be no more than 26 psi. The tire sidewall says no more than 44 psi max. My mechanic says to split the difference, and sets them to 35 psi so the fuel mileage will be better. Who's right, and why?
LES BENEDICT
VIA INTERNET

The tire sidewall's information is generic--the tire manufacturer can't know what kind of vehicle you're putting those tires on, so it only gives you a number that won't damage the tire at its maximum load. That's why it says 44 psi max. Nissan says 26 psi to give you the best compromise between handling, ride quality and safety. Your mechanic is correct that adding another 10 psi will improve fuel economy--but this might degrade the vehicle's rollover or spinout characteristics. An expert driver can determine this sort of thing at a racetrack by measuring things like tread temperature and slip angle under controlled conditions. We do this all the time when we test cars here at PM. And we usually use the vehicle manufacturers' recommended maximum cold inflation pressures. Violate them at your own risk. Just be sure to use a good gauge and to set the pressures when the vehicle hasn't been driven more than a few blocks. If you must, set the pressures above normal at the service station, then bleed off excess pressure at home the next morning.

Do You Have A Car Problem?
Just ask Mike about it. Mail your questions to Auto Clinic, POPULAR MECHANICS, 810 Seventh Ave., New York, NY 10019. While letters, faxes, phone calls or e-mail cannot be answered individually, problems of general interest will be discussed in the column.

• Mitsubishi Technical Service Bulletin (TSB) 03-26-002 says that if the front wheel bearings on your 2001-03 Montero sport utility vehicle are prematurely worn-out, water may have seeped past the seals and into the bearing. Replacing the bad bearing/hub assembly with a revised part is the recommended factory fix.
• You still can't figure out how to set the alarm on your 2001-03 Toyota Sequoia to keep it from squawking when you use the keyless remote entry fob to open the door? The good news is that you're doing nothing wrong--there's a new Body Electronic Control Unit to eliminate the problem. TSB EL007-03.
• Does your 2001 Hyundai XG300 act like it's in molasses for the first mile or so after a cold start on hot, humid days? Your Hyundai dealer can reprogram the Engine Control Module to remedy this. TSB 03-36-013.